Drawing machine



1953 o. M. STONE 2,648,908

DRAWING MACHINE Filed July 14, 1950 u 6 Sheets-Sheet 1 3 PLAN v/zw 3 A2(PP) PICTURE PLANE A A, A2 A3 A f REGULAR FRONT T h 5 ELEVATION VIEWPERSPECTIVE 5,4515 L/IVE wzw PIC TURE IN V EN TOR.

OLIVER M STONE 0. M. STON E DRAWING MACHINE Aug. 18, 1953 r 6Sheets-Sheet 2 Filed July 14, 1950 INVENTOR.

OL/VER MSTONE ,fiw Jg-xjwr 6 Sheets-Sheet 3 O. M. STONE DRAWING MACHINEAug. 18, 1953 Filed July 14, 1950 INVENTOR.

OL/VL'R M STONE W 12M;

8, 19 3 o. M. STONE 2,648,908

DRAWING MACHINE 6 Sheets-Sheet 4 Filed July 14, 1950 /3a 7 a 6 \f @u@%minimum IN VEN TOR.

OLIVER M STONE 1953 o. M. STONE 2,648,908

DRAWING MACHINE Filed July 14, 1950 e Sheets-Sheet 5 F/G. 9 H6. 8

INVENTOR.

OLIVER M. STONE 8, 1953 o. M. STONE 2,648,908

DRAWING MACHINE Filed July 14, 19 0 e Sheets-Sheet e INVEN TOR.

OL/VER M. STONE Patented Aug. 18, 1953 UNITED STATES PATENT. OFFICEDRAWING MACHINE Oliver M. Stone, Cleveland, Ohio Application July 14,1950, Serial No. 173,797

23 Claims. 1

This invention relates to drawing apparatus employed by draftsmen inmaking perspective drawings.

There are several well known methods or principles by which perspectivedrawings may be constructed such as the so-called vanishing poin methodand the visual ray method. Manual construction of perspective drawingsaccording to these methods requires considerable time and operatorskill. Efforts have been directed toward the building of drawingmachines with the object of lessening the time required and simplifyingthe operations involved in making these drawings. While these effortshave resulted in machines that have succeeded to some degree inshortening the drawing time necessary to manually construct perspectivedrawings, the machines generally are quite costly, are bulky andcumbersome to handle and to operate, andin several instances must besupplemented by manual graphical construction on the part of theoperator.

An object of the present invention is to provide a perspective drawingmachine with which accurate perspective drawings may be made fromregular plan and elevation views without the aid of construction lines.tion are the provision of a machine that is simple to operate and whichrequires nospecial skill in the operator; the provision of a machinewhich permits the operator to make stereoscopic pairs of perspectivedrawings substantially simultaneously and rapidly; the provision of amachine which permits the operator to plot all spacial points of anobject in the perspective view, including those points on the plan viewof the object that lay in or close to the picture plane; the provisionof a machine which utilizes regular plan and elevation views of theobject to be drawn and which permits the plan and elevation views to beproperly oriented with respect to the operator and to stand in the samedirection; the provision of a machine which includes a minimum number ofbars and beams and structural components whereby to facilitate andsimplify operation of the machine; the provision of Other objects ofthis invenvision of a machine which includes means for adjusting allmembers. for alignment.

Other objects of the invention will become apparent from the followingdescription of a preferred form thereof, reference being had to theaccompanying drawings in which: Figure 1 is a diagram illustrating thetheory of the present invention; Figure 2 is a simplified schematicdiagram of a drawing machine embodying the present invention; Figure 3is a plan view of the drawing machine showing the plan pointer means inthe initial setting position; Figure 4 is similar to Figure 3 showingthe plan pointer means in a plotting position; Figure 4A shows a pair ofperspective drawings constructed with the aid of the drawing machine;Figure 5 is a plan view of a portion of the machine showing the carriageand associated components; Figures 6 and 7 are vertical sections takensubstantially on the lines 6-6 and 'I-'I, respectively, of Figure 5;Figure 7 8 is an enlarged view of a portion of Figure 6 a machine thatmay be set up and disassembled I showing details of the swivel plateassembly; Figures 9, 10 and 11 are vertical sections taken substantiallyon the lines 9-9, I 0-I 0 and I I--I I, respectively, of Figure 5;Figure 12 is a plan view of a portion of the machine showing the slidepiece and the connection of the elevation beam to the clamp member;Figure 13 is a vertical section taken on the line II-II of Figure 12;Figure 14 is a plan view of a portion of the machine showing the supportplate assembly and the support assembly for the elevation beams; Figure15 is a vertical section taken on the line I5-I5 of Figure 14; Figure 16is a side elevation of a foot pedal employed in connection withconstruction of stereoscopic pairs of perspective drawings, a portion ofthe pedal being broken away to show details of construction; and Figure17 is a schemati-c view of certain components of the drawing inachineshowing the position of cords and puleys.

The perspective drawing machine which embodies the present invention isdesigned to operate on the revolution principle of graphicalconstruction. This principle will be understood by first considering theactual'condition of a human observer viewinga distant object such as ahouse. The house and the observer both stand on a common base, theground, and both project upwardly from it into the air; The observersview of the house, that is, the view which his eye sees, is made up ofmany separate views of the respective points on the house; the separateviews meld together to form the whole picture. 'Thus lines of sight orvisual rays from his eye to the many points on the object define oroutline the picture he sees. This picture is called the perspectiveView.

If a perspective drawing machine were constructed to simulate the actualcondition of an observer viewing an object, certain of the componentparts of the machine would necessarily project above the base plane by adistance representative of the height of the observers eye above theground. such a machine would be difficult to operate and henceimpracticable. According to the present invention, however, this machineis made practicable by simply revolving the vertically projectedcomponents of the machine into the plane of the base. The part of themachine which represents the observers eye will then lie substantiallyin the plane of the base; however, the length of the respective lines ofsight or visual rays remain unchanged, that is, the length of these raysrepresent true distances between the observers eye and points. on theobject.

Referring now to Figure 1, the object selected for showing the methodused in plotting the points in the perspective view is a rectangularprism. It will be understood throughout the description of the machinethat objects other than rectangular prisms may be used as the subject ofa perspective drawing on my machine. The rectangular prism therefore isillustrative of but one of many objects that may be drawn on my machineand is selected herein for illustration because of its simplicity andfor clarity of explanation.

The location in the perspective view T of any point on the prism may befound by applying the following graphical method to the location ofpoint A1 on the rear corner of the top surface of the prism. A linerepresenting the picture plane is first drawn. The plan view P is thenorientated with respect to the picture plane to the desired angle formaking the perspective view. The point E is located by spacing same fromthe plan view P by a distance representative of the horizontal distancebetween a human observer and the object being viewed. A line 7 is thendrawn to connect the chosen point A1 on the plan view with point E. Theline 1" is the horizontal projection of the visual ray from the point ofobservation to the object.

Point F designates the intersection of line A1E with an arbitraryvertical reference plane, called a pictureplane, which intersects thebase plane along the line PP between the plan view P and the horizontalprojection E of the observation point D. From F, a line p perpendicularto the line PP is drawn. The line p locates the position of point A1 onthe perspective view in a direction parallel to the picture plane; thatis, the exact location of point A1 on the perspective view liessomewhere along the line 10.

With the line A1E drawn, point B is located by laying off on aperpendicular to the line AlE a distance it which represents the heightof the point A1 above the ground or base line. This distance it isobtained from a regular elevation view S. The point D is then located bylaying oil a perpendicular to the line A1E through the point E, theperpendicular having a length equal to the height of the observationpoint above the ground or base plane. Thus, the line DE represents theheight of the observers eye above the ground. Points B and D are thenconnected by a line to complete the trapezoid AIEDB.

The next step is to lay oif a perpendicular to the line AlE throughpoint F and extend that perpendicular until it crosses the line BD,thereby locating point C. The length t of the line CF represents theheight of the point A1 in the picture Plane above the base line. Bylaying off the distance 1? above the base line and on the line 32 whichhas been drawn previously, the position of point A1 in the perspectiveview T is located.

Having thus located one point in theperspective view, the other pointsmay be-located in the same manner, the distance DE remaining constantthroughout the drawing operation. It will be noted that the height hwill remain the same for all points on the top of the rectangular prismbut that the length if of line CF will vary. As other points on theprism at a difierent distance or height above the base line are to bedrawn, the length it of the line A113 is changed accordingly.

Figure 2. is a simple schematic diagram. of the proposed perspectivedrawing machine embodying the present invention. The diagram is shown inthree dimensional form, the dotted lines representing components of themachine whichjnormally would project upwardly from the base plane if theactual condition of an observer was to be simulated; Wheneverconvenient, reference letters indicating the, intersection ofconstruction lines in Figure 1 are used in Figure 2 in the descriptionof corresponding component parts of the drawing machine.

The eye of a human observer is represented by D. The line of sight ofthe observers; eye to the top of the rectangular prism being viewed isindicated by the line D B. The true perspective height of a point on theobject will be the height of the point of intersection of the observer's line of sight with the picture plane above the base line. Thisis indicated by the point C, the perspective height being the length ofC'F; If the trapezoid DB'A1E is revolved about the intersection of theplane of this trapezoid' with the base plane, thats is, revolved aboutthe line AiE until the trapezoid lays in the plane of, the base, theactual condition of an observer viewing, an object is maintained withoutdistortion and without variation or change in the true distancesrepresentative ofthe actual physical observation condition. Thus, thetrapezoid DBA1E is the vertical plane D'E'A1E revolved into and lying inthe horizontal or base plane.

It will be noted that the length of C'F represents the true observedheight of the top rear corner of the prism inthe picture plane;therefore, CF kewise represents the true observed height of this pointon the prism. similarly, for other points on the top of the prism,

the length ofline-CF will represent'trueobserved heights of selectedpoints on the prismabove the base plane and inthe picture plane.Changesin the length of the line CF are directly proportional to thedifferences in observed heights-cf" various points on the prism withrespect to a baseline. As will be explained in detail later,variationsin the length of the line CF'are utilized to accomplish themechanical plotting of points in the perspective view.

Before describing the details ofconstruction of the perspective drawingmachine which operates on the above described principle of constructionof perspective drawings, it will be helpful to note that the schematicdiagram of Figure 2 represents a simplified skeleton of the finishedmachine. The point E is a pivot point about which the trapezoid DBAiE isadapted to pivot. The mechanical components DE and CF and A13 remainperpendicular to the component EFA1 during all plotting operations. Theintersection of components EAi and CF, that is the point F, remains inthe picture plane during pivotal movements of the components about thepoint E. The length of components EF, DE, and 3A1 are adjustable. Theintersection of components DB and CF, that is the point C, is connectedto a tracing element in such a manner that variations in the length ofCF produce corresponding variations in the position of the perspectiveplotting means toward and away from the picture plane.

APPARATUS As shown in Figures 3 and 4 the perspective drawing machine ismounted on a fiat L-shaped drawing board or base B which is adapted tobe supported in an elevated position for convenience for the operator.Extension. B of the drawing board B may be hinged to the main body ofthe board in order that the same maybe folded into a convenient size forstorage. An elongated channel shaped main guide bar I is removablyfastened at its ends to the base 13 and extends transversely of it. Acarriage generally indicated at 2 is supported on the drawing board formovement thereover and along the guide bar I. A channel member 3 issecured to the right end portion of carriage 2, as viewed in Figures 3,4 and 5 and extends from the carriage parallel to the base B andperpendicular to the guide bar I.

The channel member 3 moves with the carriage 2 over the base B andsupports a stem assembly 4 and an extension bar 5 for movement indirections perpendicular to the guide bar. An elevation ruler E and aperspective plotting member I are connected to and extend from stemassembly 4 for movement therewith in directions parallel to andperpendicular to the bar I. The elevation ruler 6 spans a regularelevation view S of the object to be drawn, which view is disposed on orattached to the surface of base B under the ruler 6. The member Ilikewise spans a sheet of drawing paper on which the perspective View Tof the sheet is ultimately to be drawn. An auxiliary elevation ruler 8,if desired, may be connected to the upper end of the extension bar 5 asviewed in Figures 3 and 4 to permit an additional regular or auxiliaryelevation view S to be used in conjunction with the regular elevationview S in the construction of the perspective drawing.

Mounted on the left end of the carriage as viewed in Figures 3, 4 and 5is a swivel plate assembly 9 which is adapted to pivot in a horizontalplane about a vertical axis indicated at Ill. Guide rods II areconnected to the assembly 9 and project therefrom away from carriage .2parallel to base B. Rods I I are parallel to each other and supportslide piece I2 for sliding movement thereover. A plan beam I3 extendstrans versely of the carriage and is supported for transverse movementon swivel plate assembly 9. Plan beam l3 therefore is adapted to slideacross the carriage 2 as well as to pivot with respect to the carriageabout the vertical axis IE3. A height rod I4 which is connected to theend of plan beam is extends therefrom at a right angle to thelongitudinal axis of beam 53, and supports a clamp I5 which is adaptedto be moved over and clamped in selected positions on rod I4. A pointerI6 clearly shown in Figure 4, is disposed on the end of the plan beam I3adjacent the height rod 6 I4, and is used as a means for locatingvarious points on the plan view P of the objectto be drawn.

A support plate assembly generally indicated at I? is removably anchoredto extension B of base B and has a yoke member I8 which pivots in ahorizontal plane about a vertical axis indicated at I9. Plan beam I3 issupported by the yoke I8 and is free to swing or pivot about the axis I9as well as to move in directions transversely of the assembly H. Anelevation rod 23 extends from assembly I! perpendicular to thelongitudinal axis of plan beam I3 and is connected to the assembly I'Iso as to pivot about axis I9 along with yoke I8. Rod 25! carriesasupport assembly 2i whose position on rod 20 is adjustable. Assembly 2!supports elevation beam 22 for pivotal and transverse sliding movementrelative to rod 28. Beam 22 extends substantially transversely of guidebar I and is pivotally connected at one end to clamp I5. The beam 22extends through slide piece I2 so as to have a pivotal and slidingconnection therewith; that is, slide piece I2 moves along guide rods I Ias a result of a lateral shift of the cross over points of elevationbeam 22 and guide rods II when pointer I6 is moved to various points onthe plan view P. Slide piece i2 is tied by cords 96 and 91 or othersuitable means to stem assembly 4 so that movements of the piece I2 onguide rods I I are exactly duplicated by movements of assembly 4 andconsequently ruler 5 and member 'I in directions perpendicular to guidebar I.

Having briefly described a general layout of my perspective drawingmachine it will be helpful to note that some of the mechanicalcomponents described above have their counterparts in the schematicdiagrams of Figures 1 and 2. For example, the pivotal axis Ifl of theswivel plate assembly 9 corresponds to the point F; slide piece I2corresponds to point C on the schematic diagrams and the variabledistance between piece I2 and axis ID of the swivel plate assemblycorresponds to the variable length t of the line CF in Figures 1 and 2.Plan beam I3 represents the line A1E which is the horizontal projectionof the visual ray DB; elevation beam 22 represents the visual ray DB;height rod I4 corresponds to the line AB and the selected position ofclamp I5 on height rod I4 is comparable to point B. The pivotal axis I9of yoke I8 in assembly I? corresponds to point E and elevation rod 2!!corresponds to line DE. The adjustable position of pivot member 2I onelevation rod 20 is represented by the point D. Elevation beam 22 whichis pivotally connected to clamp I5 and which crosses guide rods II andslidingly and pivotally engages slide piece I2 on rods II, isrepresented by the line DB or the visual ray which terminates at point Bcorrespondingly to clamp I5, crosses line CF corresponding to rods ll atpoint C represented by slide piece I 2.

The following is a detailed description of the various components thatmake up my perspective drawing machine. Referring now to Figures 5 and9, the main guide bar I consists of a straight channel shaped memberwhich extends the full length of the drawing board B and is removablysecured thereto at its ends by suitable means such as clamp screws 25,see Figures 3 and 4. The carriage 2 which rides along the main guide barconsists of two channel members 30 and 3| disposed on either side ofguide bar I and secured together by a plate 32 fastened by.

screws or the like to their top sides. The inner legs 33 and 34 ofchannel members 30 and 3|, respectively, are spaced from the sides ofthe guide bar I and antifriction rollers 35, 36, 31 and 38 carried 'bythe channel members 36 and 3| so as to rotate about vertical axesmaintain rolling'contact with the sides of guide bar I to guide themotion of carriage 2 along the guide bar with a minimum of resistance.The carriage 2 is supported for movement on the base B preferably by twosets of antifriction wheels 39, 4B, and 4|, 42 which rotate about shaftsi3 and 44 and 45 and 46, respectively, mounted on opposite ends ofchannel members 30 and 3i. These wheels are disposed to rotate about thehorizontal axes of the respective shafts and maintain rolling contactwith the surface of the base B. This construction permits carriage 2 tohave guided, substantially frictionless movement over the base B. Itwill be understood that the rollers described above are constructed soas to minimize frictional resistance between the carriage, guide bar andbase. Rollers of this type are also employed on other components of thedrawing machine to support and guide same in movements relative to eachother and to the base. It is desirable that friction between movingparts of the machine be minimized not only to facilitate operation ofthe machine but also to increase accuracy in the construction ofperspective drawings.

(a) Elevation ruler and plotting member In order to guide movements ofthe elevation ruler 6 and the plotting member 1 parallel to andtransversely of guide bar I, channel member 3, see

Figures and 10,. which extends away from guide bar I and spaced frombase B is connected at one end thereof to the carriage 2. The oppositeend of channel member 3 has a supporting wheel 51 rotatably mountedthereon and which is adapted to roll on the top. surface of base B tosupport member 3 for movement over base B in directions parallel toguide bar l. Member 3 extends under plate 32 of the carriage 2 and isattached to it by three screws. 52 which is attached to channel 3| forrotation about a horizontal axis project slightly above the top surfaceof plate 32 to support an extension bar 5. Member 3 constitutes a baseon which the elevation ruler 6 and the plotting member 7 move toward andaway from the carriage 2, as will be described below.

A stem assembly generally indicated at 4 is sup-- ported on member 3 formovement thereover in directions perpendicular to guide bar I. Stem as.-sem-bly lccnsists of spaced side elements 56 and 57' connected togetherby a plate 53, see Figures 5, 11 and 17. Elements 56 and 5! are disposedon opposite sides of channel member 3 and spaced slightly therefrom andhave rearwardly extending flange portions 58 and 60, respectively, in

which recesses are formed to accommodate guide rollers BI and 62.Rollers 6! and 62 rotate about shafts 63' and 64 connected to flanges 59and 6B and maintain rolling contact with opposite sides of member 3 toguide movements of assembly 4 therealong. Plate 58 has notches 65' and66 formed therein toreceive wheels 61' and 68 which roll on the topsurface of channel member 3' and support stem assembly 4 for movement indirections perpendicular to guide bar I. This movement is alsocontrolled by two adjustable rollers 69 attached to plate 32".

Elevation ruler 6 which consists of bar T0, a

fine wire- H and space wire supporting posts 72' Rollers 53 mounted onthe bracket.

and-'13-is connected to and extends from the stem assembly 4' so as tomove therewith. One end of bar Hi is secured to element 56 of stemassembly 4 by suitable means such as screws M. The other end of bar hasa vertically disposed pin 75, having a smooth rounded end 15a in contactwith surface B, see Figure 11', to support and permit free movement ofthe elevation rulerover base B. The ruler 6 spans a regular elevationview S of the object being drawn, the wire H serving as a straight edgeto facilitate accurate setting of other parts of the machine tocorrespond to a particular height on the object. The plotting member 1-consists of a bar 7'8 and plotting guides 11 and 78, see Figures 3 and4, whose positions on bar 16 are adjustable. Bar 76 is secured at oneend to element 57 of the stem assembly by screwmeans' l9 and has a pin8&1 similar to pin 15 in ruler 6' at its outer end to support same onbase B. Thus, member I and ruler 6' may move directly withthe stemassembly parallel to channel member 3 and also in directions parallel tothe guide bar I in response to movements of the carriage 2 therealong.V-shaped recesses 81 and 32 in guides 11 and 78, respectively, guide thepoint of a marking object, such as a pencil, for the purpose of plottingpoints on the perspective View on a suitable sheet of drawing paperunderlying the plotting member.

In order to utilize an additional and/or auxiliary elevation view inconnection with making perspective drawings, an auxiliary elevationruler 8, shown clearly in Figures 3 and 4, is provided. Ruler 8 isesscntialiy the same as ruler 6 and overlays an auxiliary elevation viewS fastened to base B on the opposite side of the carriage from elevationview S. In order to coordinate movements. of auxiliary ruler 3 withmovements of stem assembly t, an extension bar 5 which overlays channelmember 3 is connected to plate 58 of the stem assembly by screws 85. Thebar 5 is supported on rollers 53 adjacent the carriage 2 so as to movefreely in directions perpendicular to the main guide bar in response tosimilar movements of stem assembly 4. The outer end 5a of the bar 5 issuitably secured to ruler 8 which extends therefrom parallel to ruler 6.A. pin 85 similar to pin 15 of ruler 6 is carried by the outer end ofruler 8 and supports same for movement over the base B. The ruler 8 withthe wire 83 serving as a straight edge overlies an auxiliary elevationview 3 of the object being drawn. Auxiliary ruler 8 functions in thesame manner as elevation ruler 6 and provides greater flexibility in themachine by permitting auxiliary elevation views to be used convenientlyin the construction of perspective drawings.

In order to effect movements of the stem assembly 4 along channel member3 in directions perpendicular to the main guide bar I, a pulley 9G ismounted on channel member 3 remote from the carriage 2,. the pulleybeing mounted so as to rotate about a vertical axis, see Figures 5 and1'7. Similar pulleys s: and 92 are mounted on the carriage 2 near thepoint of connection of channel member 3 to the carriage. Pulley 9! isspaced from the top of carriage 9i by means of a plate 93 and a spacingblock 94. The other end of plate 93 is formed to cover the upper end ofa shaft 95 suitably fastened to plate 32 of carriage 2 and: about whichthe lower pulley $12 is disposed to rotate. The axes of pulleys ill' and92' are aligned in a plane parallel to the longitudinal axis of the mainguide bar I and, as with pulley 90,. have annular V-shaped recesses ontheir peripheries for receivingcords 96- and 97 there-' around. The endsof cords 96 and 91 are connected to the slide piece I2 and to the stemassembly 4 and are disposed around pulleys 90, 9E, 92 and I64, thelatter being mounted at the extreme outer end of guide rods l I, seeFigures 3, 4 and 1'7, to effect movement of the stem assembly 4 indirections transversely of the main guide bar in response to movementsof the slide piece I2 along guide rods II. This movement of the stemassembly 3 by cords 96 and 91 will be xplained in detail later.

(b) Swivel plate assembly In order to support plan beam 53 for pivotaland sliding movement with respect to the carriage 2 during plottingoperations, a swivel plate assembly 9 is mounted on the left end of .thecarriage as viewed in Figures 3, 4 and 5. The assembly 9 consists of aswivel plate I88, and guide members lei and I32, each of which issecured by screws or the like to the plate Ills. Members NH and I82preferably are made of short lengths of aluminum having horizontallydisposed legs I33 and I04, respectively, which are fastened to the plateIilfi. Members Illi and I62 also have vertically disposed legs H35 andI85 respectively, which are laterally spaced so as to receive and guidethe plan beam I3 therebetween. Guide rollers ml and its on the membersHit and I62 respectively engage the sides of the plan beam and atransverse supporting roller I69, see Figure '7, carried by a pinbetween plate 469 and members IiiI and IE2 engages the underside of theplan beam to facilitate sliding movement of same with respect to thecarriage.

Guide rollers Hill and M38 as well as other guide and supporting rollersassociated with other components of the machine are mounted thereon bymeans of eccentric sleeves, adjusting screws and the like which permitthe axes of these rollers to be shifted slightly for the purpose ofeffecting accurate adjustment of same. For example, rollers IE8, seeFigures 5, 6 and '7, are mounted on eccentric sleeves Illila which havehexagonal shaped heads to facilitate turning same to effect theadjustment rollers lite against the side of plan beam I3.

As shown in Figure 5, plate tilt is preferably formed with a curvedouter edge Hills and a projecting portion lit about which the plate isadapted to swivel or pivot. The plate It?! is supported for pivotalmovement by a roller ill, see Figures 6 and '7, which is journaled inchannel member 36 of the carriage 2 and which projects through slots inthe members 38 and 32 to supl portingly engage the underside of theplate its. Another roller II 2 disposed to rotate about a horizontalaxis is mounted on a bracket I53, secured to plate 32 of the carriageand engages the top surface of the plate use and in conjunction withroller Iii guides the plate its in its pivotal movements.

The projection iii of the plate IE8 is provided with an aperture 5 id,see Figure 8, through which the shank lit of a pivot stud H5 is adaptedto extend. The upper end of the shank MS has a flange II'I which abutsthe top surface of plate I06 and the lower end of shank MS is threadedas indicated at i 58. The shank Hi5 of pivot stud I I5 also extendsthrough the carriage plate 32 which extends under and is slightly spacedfrom the swivel plate Hit and through the web 3i (a) of carriage channelmember M. A nut H8 fitted into a recess in the web 3| (a) enga es thethreaded portion I if) of the pivot stud lit and 10 draws the memberstogether. The vertical axis of the pivot stud H5 which coincides withthe axis IE! of the assembly 9 is the axis about which swivel plate Iand consequently the assembly 9 rotates.

In order to guide the cords 96 and El through the swivel plate assembly9 so that the cords at all times throughout the drawing operations"remain in the plane of the axis Ill, a cord guide post assemblygenerally indicated at I253 is provided, see Figures 6 and 8. The guideassembly I20 consist of an upper pair of guide rollers Ill and I2Ia anda lower pair of guide rollers I22 and I22a mounted on and disposed torotate about the shanks I23 and I24 of screws I25 and 526. The guiderollers I2I and mm and I22, and I225; are positioned between blocks I2;and I25 and plate Hill through which screws I25 and I26 pass, the blocksserving to properly position the rollers with respect to each other.Rollers I2! and I22 have internally'disposed bearings, not shown and arethus free to rotate about the axes of screws I25 and I26 with a minimumof friction. Washers I29 and I39 space the rollers from the blocks.

As shown in Figure 8, the peripheries of rollers I20, E2961, and I2I,IZIa are spaoedfrom each other and equally about the axis it of swivelplate I08 thereby defining spaces I35 and I32. The space I3I issuificiently large to permit cord 97 to pass therethrough while theperipheries of rollers I25, I2Ia lightly engage the sides of the cord.In like manner the space I32 between rollers I22, I22a is justlargeenough to permit cord 96 to pass while maintaining light engagementwith each of the rollers. -With this arrangement and spacing'of theguide rollers in the cord guide post assembly I29, cords 96 and 9! willpass through the axis of rotation of swivel plate Hill at all timesthroughout the operation of the drawing machine, that is, for thevarious angular positions of the swivel plate assembly about the axisIt. It is of interest to note that the picture plane described inconnection with Figures l and 2 is the vertical plane containing pivotaxis I6 as well as. the reach of cords 96 and ill between pulleys 91, 92and guide post assembly I26. The picture plane is parallel to thedirection of travel. of carriage 2 on guide bar I and so pivot axis Itremains in the picture plane at all times during operation of themachine.

A position plate I33, see Figure 6, is disposed in a slot in theunderside of the guide bar 5 and secured thereto beneath swivel plateassembly 9'. Plate I33 has a forwardly projecting portion I3 3 having arecess IMa underlying pivot axis Id of the swivel plate assembly. Recessi3 ia is vertically aligned with the pivot axis iii and is of suflicientsize to admit plan pointer I6 associated with the plan beam I3. Whenplan beam I3 is moved so as to position pointer It in recess I34a, thevertical axis of the pointer will coincide with an extension of pivotaxis iii, and the pointer will lie in the .picture plane. With pointerI6 disposed in recess i3 la, the machine is in the initial settingposition shown in Figure 3; while the pointeris in this position,adjustment of the position of other components of the machine may bemade to adapt the machine to plot points at different heights above thebase line. The purpose of the initial setting position will be explainedmore fully in the description of the operation of the machine. 7

' The end I3a of the plan beam I3 adjacentthe carriage 2 is providedwitha post'generally indicated at I35 to facilitate movement of "theplan pointer I during location of points on the plan view P. The postI55 consists of a lower sleeve I 37 projecting through an aperture 1.55the plan beam I3; and an upper sleeve I35 secured to the sleeve I37 byscrews I45 and 114011 and having a flange 739a which'may be convenientlygrasped in the fingers of the operator. Disposed within the sleeves I37and I 35 is a vertically slidable stud member I42 having an enlargedcentral bearing portion I41. The upper end of stud I42 is threaded toreceive a finger knob I43 by which stud I42 and this pointer I5 may bedepressed. A spring I44 is disposed between the upper sleeve I39 andknob I44 concentrically of stud I42 to yieldingly urge the stud 42upwardly in the post. The other end of the stud member is also threadedand passes through an appropriate aperture in an extension piece I45 towhich pointer I6 is fastened. Lock nuts I 46 secure extension piece I 45on the stud I42. Pointer I5 is normally 'urged upwardly away from thetop surface of the base .B by the action of spring I44 on stud I42.During tracing operations when it is desired to bring pointer I5 incontact with a particular point on the plan view 1?, knob I43 isdepressed against spring I45 and pointer I6 is moved into contact withthe plan view.

A block I47 is suitably secured to the under.- side of the end I5a ofplan beam I3 by screws I48 and I40a. and has a .hole I49 drilled thereinperpendicular to the longitudinal axis of plan beam I3 for receiving theend of height rod I4. The height rod I4 is removably retained in holeI49 of the block I47 by a set screw I50. Rod I4 projects from block I47and is spaced from and substantially parallel to the plane of base B. Aclamp member I5, shown in Figures 12 and 13, is supported for movementover and adapted to be clamped at selected positions along the heightrod I4. The member I5 has a clamping portion I 52 which is slotted atI53 and which has .a transverse hole I54 passing therethroughintersecting the slot I55 and through which height rod I4 extends.Projecting upwardly from clamping portion I52 is a post I55 having .aflanged portion I55a fastened to the top surface of portion I52 byscrews, not shown, and a threaded stud I55 disposed within post I55. Thelower end of stud I55 threadedly engages portion I52 of the clamp belowthe slot I 53. Normally, rod I4 fits loosely in hole I54 sothat clampmember I5 may be moved to any selected position on rod I4. To secureclamp I5 in position on rod I4, knob I57 and consequently stud I5 areturned about their common vertical axis which results in drawing theslotted portion I52 tightly around rod I4. Knob I57 and post I55 providea convenient means for manipulation of the clamp by the operator.

The clamp I 5 also has an extension portion I 58 projecting therefromwhich has a pivot hole I59 formed therein. Extension I58 overlays theend of elevation rod 22 and is pivotally connected v thereto by a pinI60 disposed in hole I59 of the extension I53 and an aligned hole I6I inthe end of elevation rod 22. The extension portion I58 of clamp I5 isadapted to slide under slide piece I2 with the axis of pin I 60 inalignment with the axis of pivot sleeve I77 of the slide piece I2 asshown in Figures 12 and 13 when the pointer I5 is in the initial settingposition. When pointer I6 is in the initial setting position, the commoni2 axis of pin I60 and sleeve I77 lies in the picture plane.

The slide piece I2 is supported on and guided for sliding movement alonga pair of guide rods I I. These rods, preferably having a circular crosssection, are spaced from and parallel to each other and are connected tothe swivel plate assembly 9 so as to pivot about the axis I5 the-reof.The rods II extend outwardly from the as- .sembly 9 substantiallyparallel to the base B and have their longitudinal axes perpendicular tothe longitudinal axis of plan beam It at all times during plottingoperations. The end portions of rods I I adjacent the assembly 5 extendthrough apertures in the legs I 55 and I 55, see Figures 5, 6 and '7 andare fixed thereby by a clamp block I52. Block I 62 is fastened to guidemember MI by suitable means such as screws, and is provided with a pairof holes in which the rods II pass and are clamped. The outer ends ofrods II remote from the assembly 9 are fastened in a link I53. A pulleyI64 mounted on link I53 for rotation about a horizontal axis is similarto pulleys 95, 5i and 52 described previously, and acts as a directionreversing means for cord 57.

The slide piece I2 which rides or slides on the guide rods II consistsof a top plate element I65 connected to a front slide block I57 and rearslide blocks I58 and IE5. The blocks I57, I53 and I59 are provided withtransverse apertures or holes for slidingly receiving guide rods II tosupport the slide piece I2 in movements thereover. Guide rollers I andI7! are mounted on a bracket I72 carried by the front block I67, on itsunderside, the guide rollers being rotatable about vertical axes withtheir peripheries in contact with opposite sides of elevation rod 22 toactuate slide piece I2 by movement of rod 22 with respect to guide rodsI I. Bracket I72 is pivotally connected to the front block I57 by meansof a pivot sleeve I77. This construction of the slide piece I 2 permitselevation rod 22 to move transversely of the slide piece and at the sametime to pivot about the axis of sleeve I77. Stud I73 and lock nutsthereon retain the pivot sleeve in the aperture in the front slide blockI 57.

An aperture I74 extending through the front block I57 of slide piece I2parallel to the guide bars II is formed to permit cord 55 to passthrough the slide piece assembly on its way to the pulley I54. Theaperture I74 also extends through the pivot sleeve I77 as shown inFigure 13 so that the cord 55 at all times passes through the axis ofpivot sleeve I77. Side plates I75 and I76 are secured to the outer edgesof the slide piece I2 and furnish a means for tying the ends of cords 96and 97 to the slide piece 72. The

points of connection of cords 55 and 97 to side plates I75 and I75,respectively, are aligned and lie in the vertical plane of the axis ofpivot sleeve I77.

(0) Support plate assembly The plan beam I5 is supported remote from thecarriage 2 on a support plate assembly generally indicated at I7. Thesupport plate assembly I7 is connected to the edge of the drawing boardextension B and not only pivotally and slidingly supports plan beam I3but also includes means to limitedly shift the rear support of plan beamI3 and elevation rod 22 in directions parallel to the main guide bar I,that is, parallel to the picture plane, to facilitate the making ofstereoscopic pairs of perspective drawings as will be explained morefully below.

Referring now to Figures 3, 4, 14 and 15, the assembly I? includes achannel member I19 mounted on and extending along the edge of drawingboard extension B and secured thereto by screws I89 which engageopposite sides of the extension B. A reinforcing channel member IBI issecured in back to back relation with chan-- nel member I79 as by screwsor other suitable means not shown and thus members I19 and I8I togetherform an I beam on which the other components of assembly H are anchored.Strips I82 and I83 are secured by screws [92a and I830, to and extendtransversely of members I19 and ISI and have screws I 84 and I95 whichbear on extension B and provide for adjusting the assembly to the base.Screws I89, I94 and I85 have knobs as shown to facilitate tightening andloosening of same by the operator during assembly and disassembly of themachine and removal of same from the drawing board.

A supporting block I85 fastened to the top flanges of members I19 and[BI by screws Ififia extends parallel to the edge of drawing boardextension B and has a pair of holes, not shown, drilled transverselytherethrough for receiving and supporting rods I87 and I 89. Rods I 87and IE8 are held tightly in block I85 by set screws, not shown, and thusare fixed in position with respect to the case B. Rods I3? and I89 aresupported to extend transversely of the edge of base B parallel to guidebar I and thus parallel to the picture plane and in turn furnishsupports for other parts of assembly II.

The outer ends of rods I81 and I88 pass through a terminal clampingblock I89 wherein they are tightly secured by screws I99. Blocks I93 andI93a which serve as a stop means to limit the sliding of yoke I9 on therods I8? and I88 are mounted on the outer ends of rods I8? and I89 thatis, to the right as viewed in Figures 14 and 15, and have transverselydrilled holes therein, not shown, which guide the blocks I93 and I 99afor movement over the rods I8! and I88. A top plate I94 furnishes a basefor movement of supported parts on rods I81 and I88 and is se- L curedat one end to the tops of blocks I93 and IBM and at its other end tosimilar slide blocks not shown, which are likewise adapted to slidealong these rods. The edge of plate I94 underlying plan beam I3 iscurved as shown at I9 ia in dotted lines to provide a supporting surfacefor a smooth bearing plate IS'I on which yoke I8 rests and pivots.

A cylindrical head I92, see Figure 15, is disposed on the underside oftop plate I94 and is movable therewith and has a pivot shaft I95projecting vertically therefrom about which the pivoting action ofassembly I? takes place. The pivot shaft I96 has an enlarged bearingportion I95 which passes through an appropriate aperture in plate I9fiwhich forms a bearing for pivotal movement of shaft I96. The axis ofshaft I96 constitutes the pivotal axis I9 about which the rearwardlyextending portion of plan beam I3 pivots during operation of themachine. The yoke I9 has a split end portion 19a which is nonrotat-ablyclamped to the enlarged portion I95 of shaft I96 by screw I99. The yokeI3 is recessed as shown at I99 to permit the mounting of supportingrollers 299 which contact the underside of plan beam It to support andto facilitate sliding or" the same over the assembly IT. A block 29I issecured by screws 29 la to the underside of the inner end of yoke I8,that is, the left end of yoke I9 as viewed in Figure 5, to furnish anintermediate support and adjustment for elevation rod 20 which is alsoheld in the cylindrical head I92 of the pivot shaft by a set screw.Thus, the yoke I8, plate I94 and the pivot shaft I96 are adapted to bemoved or shifted over supporting rods I81 and I88 and parallel to thepicture plane.

Yoke member I9 has fixed thereto a pair of laterally spaced verticallyextending flange members 292 and 203 between which plan beam I3 extendsand is adapted to move. Roller blocks 294 and 295 are secured externallyto flanges 292 and 293, respectively, and are provided at their endswith guide rollers 295, 297, 298 and 209 which guide the plan beam I3 inits transverse movement over assembly Ii. Roller block 295 is mounted onpivot shaft I96, as shown in Figure I5, and locked thereon by lock nuts2 I 9 to further stabilize the pivoting of plan beam I3 about shaft I96.

In order to limit the amount of movement of the yoke IS on rods I81 andI93, blocksl93 and I93a are provided as heretofore mentioned. Clampingscrews H2 and 2I3 having knobs 2M and IMF, respectively, are threadedthrough opp-osite ends of block I93 and are adapted to engage at theirinner ends the sides of rods IS! and I88. The purpose of screws 2|? andH3 is to permit block I93 and thus the yoke I8 and pivotal axis I9 to besecured at selected positions on rods I87 and I 88 between the limits ofshifting, movement of these parts relative to the stationary baseextension B. Screws 2 I 6 and 2 I 6a fasten the blocks I93 and I93a,respectively, to the underside of plate I94, and also serve to secure anangle member 2 IT to block I93. The outer edge 2 it of block 593a isadapted to abut clamp block I89 and limit the movement of block !93c andconsequently the movement of yoke I8 and the pivot axis in the directionalong supporting rods I92 and I98 toward the right as viewed in Figure15. In like manner, the side surface 2I9, of block I93 is oriented so asto abut against the side surfaces of support. block I and the top flangeof auxiliary channel member I8I to limit movement of yoke I9 and pivotaxis I9 to the left as viewed in Figure 15.

In order to hold the shiftable or movable parts of the assembly I! inthe position shown in Figures 14 and 15, resilient means are employed tourge block I93a into abutting contact with stationary block I99. Forthis purpose a rod 229 which extends under the drawing board extension Bbears at one end against member 2H at 22I. Rod 229 is supported forsliding movement in a guide element 222 secured to a central plate 223which is connected to channel members H9 and I3I of the assembly II. Aresilient member such as spring 223 is anchored at one end to astationary flange 225 fastened to channel member I39 and has its otherend fastened to a lug 229 which is fixed to and movable with rod 229. Anaperture in stationary flange 225 also serves to guide the movement ofrod 229 in a direction parallel to rods I87 and I98.

With the above described construction of the support plate assembly II,rod 229 is movable in directions parallel to support rods I9? and I89between the limits defined by the abutment of movable block I93a withstationary clamp block I89 at one extreme and the engagement of blockI93 with the stationary block I96 at the other extreme. Movement ofthese parts from right to left as viewed in Figures 14 and 15 stretchesspring 224 which urges rod 229 and the movable 15 parts of the assemblyI to return to the position shown in Figures 14 and 15.

The purpose of providing for shifting the pivotal axis i9 is to permitsimultaneous construction of stereoscopic pairs of perspective drawings.The stops on rods I8! and I88 are adjustable so as to limit the degreeof movement of pivot axis -9 to an amount corresponding to the averageinterocular distance of an observers eyes, that is, about 2 inches. Whenthe shiftable parts of assembly I! are in the position shown in Figures14 and 15, points on one perspective view T, see Figures 3 and 4, may belocated under guide '58 of plotting means I. When the movable parts ofthe assembly are shifted against the pressure of spring 225 to the innerlimit of travel, points on the companion stereoscopic view T may then belocated under plotting guide 3?. Thus, stereoscopic pairs of perspectivedrawings may be made simultaneously and conveniently.

In order to effect movement of pivot axis 49 as described above withoutnecessitating diversion of the attention of the operator, a foot pedalgenerally indicated at 235, see Figure 16, is provided. The foot pedalconsists of a base plate 23! and a pair of spaced brackets 232, only oneof which is shown, at one end of the base plate, and another bracket 233secured to the other end of the base plate. A pair of spaced channels235 and 235 project upwardly from the base plate and are securedpivotally to brackets 232 on a pair or" pins 235 held by adjustableclamp means 23%. A cross bar 23'! is secured to the upper ends ofchannels 235 and 235 and has an aperture 238 for receiving a threadedbushing 239 to which is s cured a hollow tube .246 for guiding a wire il-t into the pedal assembly.

A foot operated channel shaped bar it? pivotally connected to bracket233 and has its other end connected pivotally to a clamp member 243which is fastened to one end of a wire which extends from the foot pedalto the support plate assembly I'i. Wire 2 35 passes through a flexibleconduit, not shown, and is connected at its other end to member 2ll ofthe assembly H by nut and bolt means 255, see Figure 14. Wire 244extends inwardly from angle 2 l and through the flexible conduit, oneend of which is attached to stationary flange 225. The flexible conduitis looped through a guide member 255 and passes down to the foot pedal2%. Foot bar 262 is suspended above and spaced from base plate 23! byvirtue of the tension on the wire 2455 caused by spring 225 of assemblyI'l. When bar 242 is depressed, as by the foot of the operator, wire 244shifts member 257' to the left as viewed in Figures 14 and 15 whichresults in movement of the pivot axis l s of assembly ll parallel to thepicture plane and of approximately 2 inches. As will appear more fullyin the description of the operation of my machine, this shift causes acorresponding movement of plotting means "i in the same direction whichproperly positions plotting guide Tl for the location of the selectedpoint on the companion perspective view T.

The elevation rod 20, see Figures 14 and 15 is secured in thecylindrical head I92 by means of a locking screw 255 and extends throughblock 251. During assembly of the machine, yoke I8 and the cylindricalhead 92 are oriented with respect to each other so that the longitudinalaxes of rod and plan beam I3 are perpendicular to each other. Elevationrod 20 therefore is arranged to pivot with respect to the base 13 aboutshaft I96 while maintaining perpendicularity with plan beam l3throughout the operation of the machine. The outer end of rod 25 issupported for movement over base B on wheels 252 and 2-53 .pivotallycarried by support piece 251 which extends transversely of rod 25 and isadapted to be adjustably positioned therealong.

lhe rearwardly extending portion of elevation beam 22 is supported formovements transversely of and pivotally on rod 25 by a support assembly2 I, see Figures 14 and 15. This assembly consists of a member 255through which rod 25 passes and on which beam 22 is supported and clamps256 and 25? on rod 25 and on opposite sides of member 255 which havescrews 253a and 25m for releasably clamping same to rod 25 to permitadjustment of the position of assembly 23 along rod 20. A short flangedpin 255 is mounted on member 255 and is the element about which pivotingof beam 22 takes place. Guide members 259 and 255 extend transversely ofmember 255 and are laterally spaced to define a channel through whichelevation beam 22 passes. Roller blocks 261 and 252 secured to guidemembers 25d and 250 are provided with rollers 253, 25%, 255 and 256which roll on the sides of beam 22 to facilitate sliding movementthereof with a minimum of friction. Rollers 25? and 25% are mountedbeneath guide members 259 and 250 and support the beam 22. The flange258a on pivot element 258 overlies a portion of guide members 259 and266 and secures same for pivotal motion with respect to member 255 androd 29.

Support assembly 2i therefore furnishes a pivotal and sliding connectionbetween the elevation beam 22 and rod 25 while at the same time guidingmovements of the elevation beam so that its longitudinal axis crossesover the axis of rod 25 at a fixed point on rod 25 selectively spacedfrom the ax s it of assembly I'l.

Figure 17 shows the disposition of the cords 2t and 9? on the variousparts of the machine for the purpose of causing stem assembly i to movealong channel member 3 in exact response to movements of slide piece i2along guide rods 5 I (not shown in Figure 17). Cord 96 is attached atone end to a tie block 2 8i? secured to top plate 58 of stem assembly 5and is secured at its other end to the right side plate I75 of the slidepiece i2. Between these two points of connection, the cord as passesaround the periphery of pull y 92 on carriage 2 and passes between lowerguide rollers I22 and 322a of swivel plate assembly 9. Cord 9; similarlyis attach-ed atone end to block are on plate 53 of assembly 4 and hasits other end tied to the left side plate I75 of slide piece i2. Betweenthese two points of connection, cord 97 passes around pulley 56 onchannel member 3, around pulley ti on carriage 2, between top guiderollers tilt and i2ia of the assembly 5, through aperture H5 in slidepiece i2 and around pulley E55 mounted on the end of guide bars i I.When slide piece I2 moves to the right, as viewed in Figure '17 alongthe guide bars H in response to movements of elevation beam '22, cord 5?will be under tension and will exert a pulling force on stem assembly 4and to move same along channel member 3 in a direction away from thecarriage 2. Similarly, movements of slide piece I2 to the left willplace cord 95 under tension and cause stem assembly it to movetoward thecarriage 2. As heretofore mentioned the reaches of the cords 95 and 91between pulleys 92, 9| and guide rollers I2 I, IZIa, E22, IZZa,respectively, are at all times aligned and in the same vertical planewhich constitutes the picture plane.

Also, cords 95 and 9'! lie in the same vertical plane between theirpoint of passage through rollers l2l, l2la, I22 and l22a and theirconnection to slide piece I2 which plane constitutes a continuation ofthe picture plane when pointer I6 is in the initial setting position asshown in Figure 3.

Operation To illustrate the operation of my machine in the constructionof perspective drawings, it will be convenient to show the procedure forplotting point A1 on the top rear corner of the prism of which P is aplan view and S a regular elevation view, see Figures 3 and 4. In orderto orient the elevation ruler 6, pointer 56 on the end of plan beam i3is placed in the initial setting position directly under the pivot axisis of swivel plate assembly 9, see Figure 3. With pointer l6 sopositioned, guide rods 1 I are parallel to the "picture plane and theaxis of pivot sleeve in of slide piece i2 is aligned with the axis 18 ofthe swivel plate assembly and also lies in the picture plane. Theelevation ruler 6 and in particular the fine wire H thereof is thenmoved directly over the top edge of the elevation view S on which theelevation of point A1 is located. This setting of the elevation ruler 6is eifecteol by movement of clamp 15 along height rod M, which in turnmoves slide piece 12 on rods l I and finally causes stern assembly 6 tomove in response to the pullin action of either cord 96 or 91. When theWire or hair line H of the' elevation ruler is aligned with point A1 onelevation view S, clamp I is locked in position on rod l4 and themachine is ready to plot the location of point A1 in the perspectiveview.

The next step consists in placing pointer it on the point A1 in the planview P of the prism, as shown in Figure 4. This produces two distinctmovements on the machine, namely, the carriage 2 is moved to the leftand slide piece I 2 is moved to a new position on rods H. Theperspective straight edge I also moves to the leftv along with carriage2 and toward guide bar I in response to the movement of slide piece I 2.The position of plotting guide 18 on perspective straight edge 1determines the location of point A1 in the perspective view which may bemarked by a pencil or other marking means inserted through the V-shapedslot 82 in guide 18.

Other points on the prism whose height above the base of the prism isthe same as point A1 for example, points A2, A3 and A4 may be located inthe perspective view by moving pointer it over each point in the planview P and marking the location of same in the perspective View asdescribed above. When other points on the prism at a different elevationfrom point A1 are to be plotted, the pointer IE is returned to theinitial setting position, clamp I5 is loosened and moved until wire H ofelevation ruler 5 is aligned with position of the new point or points onthe elevation view S. When this is done, the plotting procedure outlinedabove is followed to plot the points in the perspective view. Theplotted points may be connected by means of a pencil to complete theperspective view T.

Although I have described the plotting procedure specifically asincluding the step of marking points under guide it, it is also possibleto trace the outline of shapes lying in any one horizontal plane. Thismay be accomplished by tracing the outline of the plan view P forexample, with pointer 16 and holding a. pencil in recess 82 of guide 18and in contact with the surface of the paper on which the drawing is tobe traced. All points at the same height or elevation may be traced inthis manner, it being neces-'- sary to reset the elevation ruler 6 asdescribed above in order to plot other points in planes at differentelevations.

In order to construct stereoscopic pairs of perspective drawings, onlytwo steps in addition to those outlined above are needed. The foot pedal23% shown in Figure 16 and described above is located under the drawing.board B preferably on the floor and near the foot of the operator.After each point is plotted under guide :78 of the perspective plottingelement 1, the foot bar 242 of pedal 23!) is depressed by the foot ofthe operator which causes the yoke I8 of assembly I! and the rod 29 toshift approximately 2 inches to the left as viewed in Figures 3 and 4and parallel to the picture plane while pointer 16 remains on theparticular point in plan View P which is being plotted. Since thepivotal axis of support assembly 2| represents the elevated observationpoint. and pivot axis IQ of support plate assembly ['1 represents theprojection of the observation point in the base plane as seen by oneeye, movement of axis [9 parallel to the picture plane by an amountequal to the interoculary distance of an observers eyes sets up acondition on the machine representative of the observer viewin the prismthrough his other eye. The physical effect of this shifting movement isto move the rearward. supports of plan beam l3 and elevation beam 22which in turn move carriage 2 and thus the perspective plotting member Ito a new position which represents the view in the picture plane seen bythe other eye of the observer.

After the operator actuates pedal 239, a point in view 'I" is markedunder plotting guide 11. When the pedal is released, the movablecomponents return to their original positions under the pressure ofspring 22 5 in assembly 17 and the machine is ready to plot'the nextpoint. This procedure is followed for the plotting of each point inviews T and T. The points as plotted may then be connected by a pencil,the resultant drawings constituting stereoscopic pairs of perspectivedrawings of the prism. It will be noted that points on drawing T areplotted at the same time that those of drawin T are plotted withoutdiverting the attention of the operator from the drawing board. Theplotting guides ii and T8 are adjustably spaced apart to effect properspacing the stereoscopic pairs of drawings T and T.

The position of support assembly 2| for elevation beam 22 on rod Zli,that is, the radial distance between the point on rod 211 over which thelongitudinal axis of elevation beam 22 extends and the pivot axis 19 ofthe support plate assembly I? is relative to the height of theobservation point above the base'plane. In other words, the assembly 2|represents the eye of the human observer. It is often times desirable toconstruct perspective drawings of an object wherein the height ofobservation is des ignated, for example, it may be specified that aground leve or below ground level View, an eye level view or a birds eyeview of the object be drawn. For this purpose I have'con- 19 Toillustrate this feature of my invention, I have shown in Figure 4 apoint M on rod 29 to which, it will be assumed, assembly 2! is moved sothat the longitudinal axis of elevation beam 22 crosses the axis of rod20 at point M. With assembly 21 so positioned and the steps followed asoutlined above to construct perspective drawings and/or stereoscopicpairs of perspective drawings, the stereoscopic pairs of views K and Kof the prism as shown in Figure 4A will result. Since the point M on rod29 is closer to the pivot axis 19 of assembly I! than the original andillustrated position of assembly 2! as shown in Figure 4, movement ofassembly 21' to point M in effect lowers the height of observation. Theperspective drawings T and T of Figure 4 may, for example, represent abirds eye view of the prism while the drawings K and K of Figure 4A mayrepresent an eye level view of the prism. It will be understood that mymachine is capable of being adjusted to different heights of observationboth above and below the base plane and other than those which I haveillustrated and described.

In event it is desirable to use an additional regular elevation orauxiliary elevation view S in the construction of the perspectivedrawing T, the auxiliary elevation ruler 8 is connected to the end ofbar 5 so as to span the view S. The ruler 8 is adjusted on bar 5 so thatits wire or hair line edge is aligned with a chosen reference point onview S at the same time that wire H of ruler 6 is set at the height ofthe same point on View S. Ruler 8 is fastened tightly to bar 5 and isthereafter used in the same manner described above in connection withruler 6.

Another feature of my invention is that the elevation views S and S andthe perspective views T and T may be oriented so that they stand in thesame direction. Furthermore, the perspective views T and T asconstructed according to my invention also stand in the same directionas does the plan view P. This arrangement of views is particularlyconvenient and helpful to the drawing machine operator by enabling himto better visualize the character of the object being drawn and tofacilitate in the proper construction of perspective views.

In event it is desired to remove the drawin machine from the drawingboard for storage or shipment, or otherwise, it is necessary that onlyfour thumb screws be loosened to disengage the machine from the drawingboard. These screws are guide bar clamp screws 25 that secure each endof guide bar I to the base B and screws I80 that secure the supportplate assembly I! to the base extension B. There are no other clamps orscrews required to secure the drawing machine to the base, which featureenables quick and convenient setup and removal of the machine.

Those skilled in the art will appreciate that various changes andmodifications may be made in my invention without departing from thespirit and scope thereof. Accordingly it is to be understood that mypatent is not limited to the preferred form of the invention describedherein, the essential characteristics of my invention being summarizedin the following claims.

I claim:

1. In a perspective drawing machine, a base, a carriage supported forrectilinear movement over said base, a plotting member carried by saidcarriage and movable over said base relative to said carriage, a planbeam and an elevation beam each disposed parallel to said base and eachsupported on laterally spaced supports for pivotal movement about a pairof common axes and rectilinear movement relative to said base, means formoving said carriage in response to pivotal movement of said plan beam,means for moving said elevation beam in response to movements of saidplan beam, and means for translating movements of said elevation beam indirections transversely of said plan beam into movement of said plottingelement relative to said carriage.

2. In a perspective drawing machine, a base, a carriage supported forrectilinear movement over said base, a plotting member carried by saidbase and movable over said base relative to said carriage, a plan beamand an elevation beam each disposed parallel to said base and eachsupported on laterally spaced supports for pivotal movement about a pairof common axes and rectilinear movement relative to said base, means formoving said carriage in response to pivotal movement of said plan beam,means for moving said elevation beam in response tomovements of saidplan beam, means for translating movements of said elevation beam indirections transversely of said plan beam into movement of said plottingelement relative to said carriage and means for maintaining fixedselected horizontal spacings between the adjacent ends, respectively, ofsaid beams.

3. In a perspective drawing machine, a base, a carriage supported forrectilinear movement over said base, a plotting member carried by saidcarriage and movable over said base relative to said carriage, a planbeam and an elevation beam each disposed parallel to said base and eachsupported on laterally spaced supports remote from said carriage forpivotal movement about a common stationary axis and rectilinear movementrelative to said base, means for moving said carriage in response topivotal movement of said plan beam, means for moving said elevation beamin response to movements of said plan beam, means for translatingmovements of said plan beam in directions transversely of said plan beaminto movement of said plotting element relative to said carriage, andmeans for simultaneously shifting the position of said supports for saidbeams in substantially the same direction as the path of movement ofsaid carriage.

4. In a perspective drawing machine, a base, a carriage supported forrectilinear movement over said base, a plotting member carried by saidcarriage and movable over said base relative to said carriage, a planbeam and an elevation beam each disposed parallel to said base andlaterally spaced from the other, separate points of support forsupporting said beams for pivotal movement about a common stationaryaxis and rectilinear movement relative to said base, the point ofsupport for said elevation beam being pivotally connected to andselectively horizontally spaced from the point of support for said planbeam, means for moving said carriage in response to pivotal movement ofsaid plan beam, means for moving said elevation beam in response tomovements of said plan beam, and means for translating movements of saidelevation beam in directions transversely of said plan beam intomovement of said plotting element relative to said carriage,

5. The machine according to claim 4which includes means for selectivelyhorizontally spacing the ends of said beams remote from said common axisin directions perpendicular tothe longitudinal axis of said plan beam.

6. A perspective drawing machine comprising a base, a carriage supportedon said base for rectilinear movement thereover, a plotting membersupported for movement parallel to and perpendicular to the path ofmovement of said carriage, a plan beam extending parallel to said baseand transversely of the path of movement of said carriage, a pivotalsupport for said plan beam on said base, an elevation beam, a pivotalsupport for said elevation beam horizontally spaced from and pivotallyconnected to the plan beam support, means for maintaining fixed selectedhorizontal spacing between said beams, a slide piece supported formovement in directions parallel to said base and transversely of saidplan beam and having a pivotal and sliding connection with saidelevation beam, and means for moving said plotting member relative tosaid carriage in response to movement of said slide piece relative tosaid plan beam.

7. A perspective drawing machine comprising a base, a carriage supportedon said base for rectilinear movement thereover, a plotting membersupported for movement parallel to and perpendicular to the path ofmovement of said carriage, a plan beam extending parallel to said baseand transversely of the path of movement of said carriage, a pivotalsupport for said plan beam on said base, an elevation beam, a pivotalsupport for said elevation beam, means for connecting said beamscomprising a rod disposed to pivot about the pivotal axis of the supportfor said plan beam in response to similar movement of said plan beam,the pivotal support for said elevation beam being selectivelyhorizontally positioned on said rod, a slide iece supported for movementparallel to said base in directions transversely of said plan beam andhaving a pivotal and sliding connection with said elevation beam, andmeans for moving said plotting member relative to said carriage inresponse to movement of said slide piece relative to said plan beam.

8. A machine for constructing perspective drawings from regular plan andelevation views comprising a planar base on which said views aremounted, a carriage on said base and movable in a straight linethereover, a plotting element supported for movement over said base indirections parallel to and perpendicular to the path of movement of saidcarriage, a plan beam disposed parallel to said base, point locatingmeans on said plan beam, a horizontally pivotal member for supportingsaid plan beam remote from said carriage, guide means anchored to saidbase, said pivotal member being mounted on said guide means and movabletherealong in directions parallel to the path of movement of saidcarriage, means for moving said carriage in response to pivotalmovements of said plan beam, an elevation beam, another horizontallypivotal member movable over said base in directions parallel to andtransversely of the path of movement of said carriage and adapted tosupport said elevation beam, means for moving said other pivotal memberin response to movement of said first named pivotal member on said guidemeans, means for co-ordinating movements of said beams, and means formoving said plotting element in directions parallel to and perpendicularto the path of movement of said carriage in response to movements ofsaid plan beam.

9. A machine for constructing perspective drawings from regular plan andelevation views comprising a planar base on which said views aremounted, a carriage on said base and movable in a straight linethereover, a plotting element supported for movement over said base indirections parallel to and perpendicular to the path of movement of saidcarriage, a plan beam disposed parallel to said base, point locatingmeans on said plan beam, a horizontally pivotal member for supportingsaid plan beam, guide means anchored to said base, said pivotal memberbeing mounted on said guide means and movable therealong in directionsparallel to the path of movement of said carriage, means for moving saidcarriage in response to pivotal movements of said plan beam, stopsassociated with said guide means to limit the movement of said plan beamsupport member, foot pedal means connected to said plan beam supportmember to actuate movement of same between the limits defined by saidstops, guide means anchored to said base, said pivotal member beingmounted on said guide means and movable therealong in directionsparallel to the path of movement of said carriage, means for moving saidcarriage in response to pivotal movements of said plan beam, anelevation beam, another horizontally pivotal member movable over saidbase and adapted to support said elevation beam, means for co-ordinatingmovements of said pivotal members, means for co-ordinating movements ofsaid beam, and means for moving said plotting element in directionsparallel to and perpendicular to the path of movement of said carriagein response to movements of said plan beam.

10. The machine according to claim 9 in which said plotting element hasa pair of laterally spaced marking means for plotting points onstereoscopic pairs of perspective drawings, one of said marking meansdefining the location of points on one of said perspective drawings whensaid plan beam support member is positioned at one limit of movement andthe other of said marking means defining the location of points of theother perspective drawing when said plan beam support member ispositioned at the other of said limits of movement.

11. In a machine of the character described, a planar base, a carriageadapted to move in a straight line over said base, a plotting element,means connecting said plotting element to said carriage for guidingmovement of said plotting element in directions parallel to andperpendicular to the path of movement of said carriage, a plan beam,means for supporting said plan beam for pivotal and rectilinearmovements relative to said base, point locating means on one end of saidplan beam, an elevation beam, means for supporting said elevation beamfor pivotal and rectilinear movements relative to said base, meansconnecting said plan beam to said elevation beam, a guide member carriedby said carriage and extending therefrom parallel to said base andperpendicular to the longitudinal axis of said plan beam, a slide pieceon said guide member and adapted to move therealong, said slide piecehaving pivotal and sliding connection with said elevation beam, andmeans for moving said plotting element in response to movements of saidslide piece along said guide member.

12. The machine according to claim 11 in which said guide member andsaid carriage have pulley means, said plotting element movement meansincluding cord means connected to said slide piece and said plottingelement and engaging said pulley means and efiective to move saidplotting element in directions perpendicular to the path of movement ofsaid carriage in response to said movement of the slide piece along saidguide member.

13. The machine according to claim 12 which includes means forsupporting said plan beam for pivotal and transverse movements relativeto said carriage, said cord means being disposed to pass through theaxis of pivoting of said plan beam relative to said carriage. 4

14. The machine according to claim 11 which includes a swivel platemounted on said carriage and adapted to pivot relative to said carriagein a plane parallel to said base, means on said swivel plate to supportsaid plan beam for movement transversely of said plate, and a positionplate fixed to said base having a recess therein alignedwith the pivotalaxis of said swivel plate, said point locating means on said plan beambeing positionable in said recess.

15. A machine for constructing perspective drawings from regular planand regular elevation views, comprising a base, a carriage mounted onsaid base for movement thereover in a straight line, a plan beam and anelevation beam each supported for simultaneous movement parallel to saidbase, point locating means on said plan beam for locating points on saidplan View, means for oo-ordinating movements of said plan beam andelevation beam, a plotting element, an elevation ruler disposed to spansaid elevation view, said element and said ruler being disposed toextend substantially parallel to the direction of movement of saidcarriage an elongated rigid member carried by said carriage and adaptedto move in directions perpendicular to the path of movement of saidcarriage, means for connecting said plotting element and said elevationruler to said rigid member, and means for moving said rigid memberrelative to said carriage in response to movements of said plan beam andsaid elevation beam.

16. A perspective drawing machine comprising a base, a carriagesupported for straight line movement over said base, a bar supported onsaid carriage for movement therewith and relative thereto in directionsperpendicular to the path of movement of said carriage, a perspectiveplotting element connected to said bar and extending therefrom parallelto the path of movement of said carriage, an elevation ruler similarlyconnected to said bar, a plan beam extending parallel to the plane ofsaid base transversely of the path of movement of said carriage apivotal support for supporting said plan beam in pivotal and rectilinearmovements relative to said base, an element pivotally connected to saidcarriage and adapted to pivot in a plane parallel to said base, saidplan beam being engageable With said element and movable transverselythereof, an elevation beam extending parallel to the plane of said baseand disposed in substantially side by side relation with said plan beam,a pivotal support for said elevation beam, a rod connected to the ivotalsupport for said plan beam and extending therefrom perpendicular to thelongitudinal axis of said plan beam, said pivotal support for saidelevation beam being releasably connected to said rod, another rodconnected to the end of said plan beam remote from the pivotal supporttherefor and extending from said plan beam in a direction perpendicularto the longitudinal axis thereof, clamp means releasably clamped on saidanother rod and pivotally connected to the end of said elevation beam,guide rod means connected to said pivotal carriage element and extendingtherefrom in a direction perpendicular to the longitudinal axis of saidplan beam, a slide piece carried by said guide rod means and mov abletherealong, said slide piece having pivotal and sliding connection withsaid elevation beam, and cord means connected to said slide piece formoving said bar in directions perpendicular to the path of movement ofsaid carriage.

17. A machine for constructing perspective drawings from regular planand regular elevation views, comprising a base, a carriage mounted onsaid base for movement thereover in a straight line, a plan beam and anelevation beam each supported for pivotal and rectilinear movementparallel to said base, an anchor member secured to said base, saidpivotal support for said plan beam being slidably connected to saidanchor member and movable thereover parallel to the path of movement ofsaid carriage, foot pedal means connected to said plan beam pivotalsup-- port to actuate movement of same, point locating means on saidplan beam for locating points on said plan view, means for oo-ordinatingmove-- ments of said plan beam and elevation beam, a plotting element,an elevation ruler disposed to span said elevation view, an elongatedrigid member carried by said carriage and adapted to move in directionperpendicular to the path of movement of said carriage, means forconnecting said plotting element and said elevation ruler to said rigidmember, and means for moving said rigid member relative to said carriagein response to movements of said plan beam and said elevation beam.

18. The machine according to claim 3 in which said last named meanscomprises guide elements supporting said plan beam support for limitedtransverse movement parallel to the path of movement of said carriage,means to limit said transverse movement of said plan beam support, andmeans to actuate movement of said plan beam support between the limitsof said transverse movement.

19. The machine according to claim 18 in which said plotting membercomprises an elongated bar extending parallel to said base and to thepath of movement of said carriage, a pair of adjustably spaced plottingguides on said plotting member, said guides locating the position ofplot points on stereoscopic pairs of perspective drawings when said planbeam support is located at the respective limits of its movement.

20. The apparatus according to claim 9 which includes a flexiblecable'connected at one end to said pedal means and at the other end tosaid plan beam support member whereby actuation of said pedal will movesaid element in one direction, and spring means connected to saidbaseand said support member urging the latter to move in the oppositedirection.

21. A drawing machine for making perspective drawings from regular planand elevation views by reproducing in perspective the image of aselected three dimensional object referred to a picture plane,comprising a base lying in plane perpendicular to said picture plane, anelongated guide bar fastened to said base parallel to and spaced fromsaid picture plane, a carriage supported for movement on said guide bar,a plan beam plvotally supported at one end on said base and havingpivotal and sliding connection with said carriage whereby pivoting ofthe beam about said one end will cause said carriage to move along saidguide bar, the pivotal connection between said plan beam and saidcarriage lying in said pictureplane, a point locating element on theother end of said plan beam for selecting points on the plan view tobeplotted, said plan beam being movable to position a said point 10-cating element in said picture plane whereby to facilitate plotting ofpoints lying in said picture plane, a plotting member and means to movesaid plotting member in response to point locating movements of saidplan beam.

22. The machine according to claim 21 in which the pivotal connectionbetween said plan beam and said carriage is spaced above said base, saidplan beam being laterally offset from both the axes of pivotalconnection of same to said carriage and to said base, said pointlocating element extending outwardly from said plan beam a distanceequal to the offset of said plan beam from said axes whereby tofacilitate positioning same under said pivotal connection and in thepicture plane.

23. In a machine of the character described, a planar base, a carriageadapted to move in a straight line over said base, a plotting element,an elevation ruler, means connecting said plotting element and saidelevation ruler to said carriage for guiding movement of same indirections parallel to and perpendicular to the path of movement of saidcarriage, a plan beam, means for supporting said plan beam for movementsparallel to said base, point locating means on one end of said planbeam, an elevation beam, means for supporting said elevation beam formovements parallel to said base, means connecting said plan beam to saidelevation beam, a guide member carried by said carriage and extendingtherefrom parallel to said base and perpendicular to the longitudinalaxis of said plan beam, a slide piece movable on said guide member, saidslide piece having pivotal and sliding connection with said elevationbeam, and means for moving said plotting element and said elevationruler normal to the direction of carriage movement in response tomovements of said slide piece along said guide member.

OLIVER M. STONE.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 406,083 Brix July 2, 1889 1,986,625 De Lorenzi Jan. 1, 19352,442,117 Davis May 25, 1948

